CN101322327A - Scheduling in wireless multi-hop relay network - Google Patents

Abstract

A first aspect of the invention relates to a wireless relaying network having a number of network nodes including a designated originating node (10), at least one relaying node (20), and at least two receiving nodes (30). Basically, the designated originating node (10) transmits a pilot signal, and the relaying node(s) (20) receives and forwards the pilot signal to the receiving nodes (30), each of which measures channel quality based on the received pilot signal. In accordance with the invention, at least part of the receiving nodes (30) feed information on the measured channel quality all the way back to the designated originating node (10), and the originating node (10) then schedules data for transmission to at least one selected node of the receiving nodes (30) based on the received channel quality information.; Subsequently, the designated originating node (10) transmits data to the selected receiving node(s) via the same relaying node(s) (20) that forwarded the pilot signal. In this way, multi-user diversity scheduling is introduced to relaying networks in a unique and efficient manner that provides significant data rate enhancements.

Description

Scheduling in the wireless multi-hop relay network

The invention technical field

Present invention relates in general to wireless network, relate in particular to the wireless relay network such as the cooperating relay network.

Background of invention

Wireless and/or the cellular system of estimating future also can provide higher data rate of covering, the support of increase or the combination of the two except that many other aspects.In addition, estimating will be more important aspect the cost of future foundation and maintenance system.Along with the increase of data rate and/or communication distance, also need to tackle the problem of the battery consumption of increase.

Be to rethink employed topology in the existing system on the one hand, this is because three generations's cellular network exists very little topology change.

For example, known is the possibility that multi-hop provides the significantly reduced path loss between communication (repeater (the relay)) entity, and this can make the user be benefited.

The topology of another kind of type is considered so-called cooperating relay.This is the field of the cooperation between a plurality of stations of research.In nearest research document, it has used some titles, such as collaboration diversity (cooperative diversity), cooperation coding, virtual antenna array or the like.In [1], provide the good summary of collaboration communication scheme.The cardinal principle benefit of the cooperation between the station in the radio communication can be summarized as the interruption (outage) (because various forms of diversity) of higher data rate, reduction, the battery useful life that increases and the covering (for example for cellular system) of expansion.

Recently, the thought with cooperating relay of less transponder (repeater) (or repeater) causes some concerns.This thought is that repeater can send cooperate the signal [2] from sender to receiver.The signal that is sent by the transmission node that starts can at first be received by a plurality of repeaters, described a plurality of repeaters with described signal parallel be forwarded to receiving node.For example, cooperation can relate to following aspect: relevant synthetic, STC (Space Time Coding such as the Alamouti diversity), and have regeneration (decoding-forwarding) or non-regeneration (amplification-forwarding) characteristic.In cooperating relay, the number of jumping is generally double bounce, promptly one jumps to relay station (one or more), and one jumps to receiving station.

The thought of cooperating relay can think to comprise the only degenerate case of the multi-hop of double bounce in some sense, but it can be summarized as and consider parallel route and the signal processing that will use simultaneously.Usually allow repeater to carry out various signal processing and coding task, it improves overall communication performance in every way.The benefit of the mechanism used can generally can be divided into diversity gain in cooperating relay, wave beam forms gain and spatial reuse gain.

Developed the many basic principles [1], [3], [4] and [5] that to be used for the cooperating relay scheme, each all has its oneself benefit and shortcoming.The cooperating relay scheme of operational excellence relies on the precise channels state information usually, but needs fast protocol and force overhead.Replacedly, relax demand, but can reduce overall communication performance usually the detailed knowledge of channel.

Summary of the invention

The present invention has overcome these and other shortcomings of prior art arrangement.

Overall purpose of the present invention provides improved cordless communication network.

It also is a purpose that improved scheduling is provided in wireless network (for example wireless relay network).

Especially, the total data rate that is desirable to provide the mean data rate of increase and the variance that reduces (variance) and increases.

A specific purpose is to distribute delivering power efficiently to via node in (chance) junction network, with further raising user data rate.

And specific purpose is-can handle the situation of destructive interference at the positive forward signal of a plurality of repeaters during to portable terminal efficiently.

Another specific purpose provides the improved method and system that is used in the wireless relay network trunk information, and the equipment/network node that is provided for supporting efficient relaying in such network.

Another specific purpose is that improved grand diversity operation is provided in cordless communication network, and the controller equiment that is associated that is connected with at least two radio base stations in such network is provided.

As being limited by appended Patent right requirement, the present invention satisfies these and other purposes.

A first aspect of the present invention relates to the wireless relay network with a plurality of network nodes, and described network node comprises specifies origination node, at least one via node and at least two receiving nodes (being also referred to as the user).Basically, specify origination node to transmit pilot signal, and via node (one or more) receives and transmit pilot signal to receiving node, each in the described receiving node is according to the pilot signal measurement channel quality that is received.According to the present invention, at least a portion receiving node will be given about the feedback information of measured channel quality on the way and specify origination node, and after this origination node data dispatch that will be used for transmitting according to the channel quality information that is received is at least one selected node of receiving node (user).Subsequently, specify origination node data to be sent to selected receiving node (one or more) via the identical via node (one or more) of transmitting pilot signal.Like this, just with provide that visible data speed improves peculiar and efficiently mode junction network is introduced in the multi-user diversity scheduling.

Under this background, the multi-user diversity scheduling allows to select the user of good transmitter-repeater (the one or more)-receiver channels of experience " instantaneous " to communicate, consider the mean data rate of increase and the variance that reduces thus, and the total data rate that increases.

Preferably, multi-user diversity scheduling relates generally to selective reception node/user among those the node/users with high channel quality, and the data that are associated with selected node of selection are transmitted being used for.Can be on relative meaning, i.e. the instantaneous channel quality of its average channel quality is relatively determined high channel quality, but also can use other mass measurements such as absolute channel quality.Although relying on (channel dependent) scheduling of channel is the core of multi-user diversity scheduling, also can consider other aspects, for example fairness among the user and user's QoS requirement.In addition, channel quality can be based on instantaneous channel or predicted channel quality.Therefore, according to make the decision that to select which receiving node/user based on the tolerance of channel quality.

Verified, the novelty thought of the multi-user diversity scheduling in the junction network is particularly advantageous for the auxiliary double bounce network of the relaying of cooperating relay network and cooperation.

Although can only use single via node, but it is useful using a plurality of via nodes, and for pilot transmission, described a plurality of via nodes concurrently and transmit pilot signal on same frequency, and for transfer of data, described a plurality of via nodes concurrently and transmit data on same frequency.When a plurality of via node forward receiving node forward signal, efficiently handles situation by in the relay structure system, merging multi-user diversity, so that the receiving node of only selecting to experience good channel quality is used for communicating by letter in the potential destructive interference at receiving node place.

For example, origination node can be base station and receiving node can be a mobile subscriber terminal.Receiving node can be any relay station usually, comprises amplification-repeater station and decoding-repeater station.

The present invention also provides the flexibility of power-controlled via node.In this aspect of the invention, preferably distribute the relaying delivering power according to the average link quality of the link between via node and receiving node selected group.Under the situation of amplifying forward relay, for example, can also distribute the relaying delivering power according to the average link quality of the link between origination node and the via node.

In another aspect of the present invention, in based on OFDM (OFDM) or OFDMA (OFDM access), multi-user diversity scheduling and following mechanism are used together, described mechanism be implemented in the receiving node parallel receive from the direct signal of origination node and repeating signal to provide directly and the constructive interference of repeating signal.Preferably, start transmission node and repeater realize this point by suitably being disposed.For example, via node can be that frequency is transmitted (on-frequency repeating) relay station, each received signal in the described relay station and under basically less than the situation of stand-by period of OFDM (OFDM) symbol duration with the same frequency band forward signal.Can use the Cyclic Prefix duration of the power delay profile of the equivalent channel that is suitable for repeating signal and direct signal to dispose the transmission node that starts, to guarantee parallel receive and constructive interference.

For when at least one in the receiving node with the transmission node that starts is equipped with a plurality of antennas and situation when being used based on the opportunistic communication scheme of MIMO-MISO, at least a portion via node can be equipped with one or more antennas, and one of them can be selected for receiving node based on the communication of MIMO/MISO to set up richer channel, is about to even further increases the channel of whole end-to-end (ETE) channel capacity.Especially, the MIMO based on spatial reuse can be used to provide high spectrum efficiency.The feedback that is used for this scheme is preferably described the channel quality vector of the quality of each MIMO subchannel.

In yet another embodiment of the present invention, introduce multi-user diversity, be used for improving grand diversity at cordless communication network in distinctive mode.At least two base stations and two or more portable terminals that cordless communication network consists essentially of controller, is connected with this controller.Pilot signal is transmitted in the base station, and receives each portable terminal measure channel quality of pilot signal.Each portable terminal will be given controller about the feedback information of measured channel quality on the way then, and this controller arrives a selected portable terminal according to the data dispatch that the channel quality information that is received will be used to transmit.At last, data are sent to selected portable terminal by the base station.

The invention provides following advantage:

Improved relaying performance.

The data rate that improves.

Power-controlled via node.

Directly and the constructive interference of repeating signal.

The potential MIMO and/or the MISO that are used for further improving operate.

Improved grand diversity operation.

When reading the following description of embodiments of the invention, will understand other advantages provided by the present invention.

Accompanying drawing is briefly described

By with reference to below in conjunction with the given description of accompanying drawing, with understand best the present invention with and other purpose and advantage, wherein:

Fig. 1 is the indicative flowchart that illustrates exemplary preferred embodiment of the present invention.

Fig. 2 is the schematic diagram based on the wireless cooperation junction network of multi-user diversity according to exemplary preferred embodiment of the present invention.

Fig. 3 is the schematic diagram based on the wireless cooperation junction network with a plurality of repeaters of multi-user diversity according to exemplary preferred embodiment of the present invention.

Fig. 4 is the schematic diagram based on the wireless cooperation junction network with power controlled repeater (one or more) of multi-user diversity according to exemplary preferred embodiment of the present invention.

Fig. 5 illustrates the schematic diagram that is used for the exemplary configuration of a plurality of repeaters of a plurality of mobile station communicates and base station.

Fig. 6 is the schematic diagram that illustrates in the relation of three kinds of different situations lower channel capacity and number of users, and all situations is all based on amplifying forward relay.

Fig. 7 is the schematic diagram that illustrates in the relation of three kinds of different situations lower channel capacity and number of users, and all situations is all based on the decoding forward relay.

Fig. 8 is according to the parallel receive of exemplary preferred embodiment of the present invention directly and the schematic diagram based on the wireless cooperation junction network of multi-user diversity of repeating signal.

Fig. 9 is the schematic diagram based on the wireless cooperation junction network of the multi-user diversity of MIMO/MISO operation according to exemplary preferred embodiment of the present invention.

Figure 10 is the schematic diagram according to the wireless network of the grand diversity operation of the employing multi-user diversity scheduling of exemplary preferred embodiment of the present invention.

The detailed description of inventive embodiments

In whole accompanying drawings, same reference numerals will be used to indicate corresponding or similar components.

Basic thought according to the present invention be with provide that visible data speed improves peculiar and efficiently mode junction network is introduced in the multi-user diversity scheduling.

Fig. 1 is the indicative flowchart that illustrates exemplary preferred embodiment of the present invention.In step S1, the origination node of appointment transmits pilot signal.In step S2, one or more via nodes also abbreviate repeater as, receive and transmit pilot signal to a plurality of receiving nodes (user).In step S3, each receiving node is measure channel quality in response to the pilot signal that receives.Next, in step S4, at least a portion receiving node is to specifying origination node to report back measured channel quality.This provides channel-quality feedback from receiving node to origination node.In step S5, origination node is carried out the multi-user diversity scheduling according to the channel quality information that receives, to be used for selection should to which (one) individual transmission data of a plurality of receiving nodes (user).After this, in step S6, origination node transfers data to selected receiving node (one or more) via the identical via node (one or more) that transmits pilot signal.This means: can from each user who receives pilot signal, select the specific user of the good transmitter-repeater-receiver channels of experience " instantaneous " to communicate, thereby realize the mean data rate that increases and the variance that reduces and the total data rate of increase.Preferably, multi-user diversity scheduling is included among those users with high channel quality and selects the user, and selection is transmitted with the data that selected node is associated.

Although the present invention is applicable to wireless relay network usually, has proved the present invention with regard to the cooperating relay network, and with regard to the double bounce network that the relaying of cooperation is assisted, be particularly advantageous especially.

Fig. 2 is the schematic diagram based on the wireless cooperation junction network of multi-user diversity according to exemplary preferred embodiment of the present invention.The wireless cooperation junction network consists essentially of specifies origination node (also being known as transmitter (TX) 10), via node or so-called relay station (RS) 20, a plurality of (U) receiving node (also to be called receiver (RX for short ₁..., RX _U)) 30.Except that normal transceiver was functional, transmitter 10 comprised pilot module 20, is used for storing and will be sent to receiver (RX ₁..., RX _U) the data queue 14 and the multi-user diversity scheduler 16 of data.Relay station 20 can be that relay station, the amplification of any routine transmitted or decoding forwarding alternatively.Except that normal transceiver was functional, each receiver of considering 30 all comprised channel quality measurement unit 32.

Origination node can for example be base station and receiving node can be a mobile subscriber terminal.Via node can be any relay station usually, for example amplifies repeater station or decoding repeater station.

At first, send (1) pilot tone via relay station 20 to receiver 30 from transmitter 10.Channel quality is measured and given the transmitter 30 that starts by report (2) by the channel quality measurement unit 32 in each receiver 30.Next, transmitter 30 adopts multi-user diversity scheduler 16, comes to dispatch which (and what will transmit) of wishing to be sent in the receiver 30 to small part according to feeding back from the CQI at least a portion receiver 30 (channel quality information).Scheduler 16 is listed the receiver of the high CQI value of report preferentially in usually, to optimize data rate.At last, transmitter 10 is selected the data that are associated with selected receiver from data queue 14, and uses according to the CQI of selected receiver and adaptive suitable modulation and encoding scheme transmits (3) data.Usually, these two all passes through same paths pilot tone and data, and the supposition channel keeps identical basically during measuring transfer of data.In other words, measure data transfer cycle and be shorter than usually or equal channel coherence time at the most, and the delivering power of transmitter 10 and relay station 20 is substantially the same or only slowly change measuring between the data transfer cycle.Owing to used relaying, i.e. equivalence is for introducing big frequency reuse distance, so reduced the influence of potential unpredictable " presence of intercell interference ".

In many cooperating relay schemes, use repeating signal (one or more) and get the nod from these two benefit of the direct signal (by the dotted line indication) of transmitter.This method normally is combined in direct signal and the repeating signal that two different (time instance) constantly receive in receiver.The present invention also is applicable to this cooperating relay scheme certainly.

And imagination, according to the present invention, can in wireless relay network, measure, so that be implemented in receiving terminal parallel receive repeating signal and direct signal, so that the constructive interference of repeating signal and direct signal to be provided based on OFDM (OFDM) or OFDMA (OFDM access).To describe this aspect of the present invention after a while in detail.

Usually, if in single-hop systems, used the chance scheduling, then less about the design influence of mobile subscriber terminal (receiving node) and base station (transmission node).Difference is that base station-user terminal design of protocol need cater to two phase retardatioies.

A plurality of relay stations

It usually is useful using a plurality of via nodes of parallel convey coherent signal.Preferably, for pilot transmission, via node concurrently and on same frequency, transmit pilot signal, and for transfer of data, it is concurrently and transmit data on same frequency.When a plurality of via nodes during, can handle situation efficiently by in the relay structure system, merging multi-user diversity, so that only select the receiver of experience good channel quality to be used for communication in the potential destructive interference of receiver side at forward signal.In addition, the receiver of experience good channel quality experiences the signal from the relevant a plurality of repeaters that increase probably, this means that will experience wave beam except that multi-user diversity gain forms gain.

Fig. 3 is the schematic diagram based on the wireless cooperation junction network of multi-user diversity with a plurality of repeaters according to exemplary preferred embodiment of the present invention.Suppose to exist U receiver and V repeater, and can use to amplify and transmit and/or the decoding forwarding.

For contracted notation is represented, for instance, adopt OFDM or OFDMA.CP represents Cyclic Prefix, and s (t) is that time-continuous signal and s (n) are the corresponding time sampling signals with sample index (sample index) n.

Amplifying under the hypothesis of forward relay, the signal of the subcarrier k that is received by each u of receiving station can be written as:

$R_u\left(k\right)=\underset{v=1}{\overset{V}{\mathrm{\Σ}}}{H}_{u,v}^{\left(2\right)}\left(k\right)\·a_v\left(k\right)\·(H_v^{\left(1\right)}\left(k\right)\·S\left(k\right)+W_v\left(k\right))+W_u\left(k\right)---\left(1\right)$

Perhaps of equal valuely:

$R_u\left(k\right)=S\left(k\right)\·H_u^{\left(\mathrm{eff}\right)}\left(k\right)+W_u^{\left(\mathrm{eff}\right)}\left(k\right)---\left(1a\right)$

Wherein:

$H_u^{\left(\mathrm{eff}\right)}\left(k\right)=\underset{v=1}{\overset{V}{\mathrm{\Σ}}}{H}_{u,v}^{\left(2\right)}\left(k\right)\·a_v\left(k\right)\·H_v^{\left(1\right)}\left(k\right)---\left(1b\right)$

$W_u^{\left(\mathrm{eff}\right)}\left(k\right)=\underset{v=1}{\overset{V}{\mathrm{\Σ}}}{H}_{u,v}^{\left(2\right)}\left(k\right)\·a_v\left(k\right)\·W_v\left(k\right)+W_u\left(k\right)---\left(1c\right)$

Wherein v is a relay station, and H (k) is multiple (complex) channel gain, and S (k) is complex-valued data symbol (for example being selected from the signal constellation point such as 16-QAM, PSK or homologue), and W (k) is the complex value noise, a _v(k) be the amplitude gain factor (also can be plural number) of repeater, and (1) in the wherein above-mentioned formula and (2) represents the link of transmitter to the link of repeater and repeater to receiver respectively.If desired, also direct link (between transmitter and the receiver) can be included in the equation.Yet,, do not comprise direct link in the above-mentioned equation for simple and clear.After a while with this situation of individual processing.

According to equation (1b), clearly, the constructive interference each other of some subcarriers.Therefore, a user can use a subclass of subcarrier resources, and another user uses another subclass.

Gain factor a _v(k) can pass in time and slowly change or measure and data phase during the free maintenance of institute constant, promptly end-to-end (ETE) channel measures transfer of data from CQI and can significantly not change.For different subcarrier k, also can carry out difference setting.In addition, the employed power of transmitter can pass in time and slowly change or measure and data phase during the free maintenance of institute constant.Yet, if the controller decision communicates gain factor a with another group user _v(k) and the transmitter delivering power can flip-flop.

In list of references [5], for example, operation dispatching is determined: allowing each transmitter-receiver when using also other transmitter-receivers public repeater storehouse (pool), which transmitter-receiver is to should being movable.Compare with the present invention, this is tangible difference.Especially can notice that list of references [5] considers that different topology, one group of transmitter-receiver are right, and the present invention's consideration is the transmission node of selecting a receiving node from a plurality of receiving nodes potentially.The present invention is specially adapted to the down link in the cellular system, and [5] more are applicable to ad hoc situation.

Power controlled repeater

The present invention also provides the flexibility of power-controlled via node, as will be explained.In this aspect of the invention, preferably distribute the relaying delivering power according to the average link quality of the link between via node and the receiving node.Under the situation of amplifying forward relay, for example, also can distribute the relaying delivering power according to the average link quality of the link between origination node and the via node.

Herein, this thought is but is not limited to-controls to the relaying delivering power that " cluster (clustered) " user organizes that described user has probably experienced identical path loss to all repeaters.Preferably determine the power setting of each repeater according to average channel gain and noise ratio feature.This allows to be used to control the energy efficient low-rate feedback of delivering power, and reason is that average channel quality is considered, and does not promptly need to follow rapid fading.

For example, supposition exists total power constraint P for repeater usually _RS, and should among the repeater of being considered, distribute described power then.Usually also supposition, related receiver all probably is exposed to the power loss of the same order of repeater in the power control.

In list of references [3-4], at having drawn optimal power allocation based on relevant synthetic system, this system allows gain and phase parameter to be adjusted to instantaneous channel status.In opportunistic cooperation trunking plan of the present invention, can not suppose this knowledge.Yet the present inventor has realized that and can use average link quality.In [3-4], drawn a kind of amplifying parameters b _v, it provides optimum SNR.With [3-4] contrast, the present invention proposes to define b on average meaning _v

For amplifying the relaying of transmitting type, amplifying parameters bv quilt is as giving a definition:

${\stackrel{\‾}{b}}_v^{\left(\mathrm{AF}\right)}=\sqrt{\frac{{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{RS},v}\·{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{MS},v}}{{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{RS},v}+{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{MS},v}+1}}---\left(2a\right)$

${\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{RS},v}={\stackrel{\&OverBar;}{G}}_{1,v}{P}_{\mathrm{BS}}/{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="RS"\; filenames="A20058005219000251.png,A20058005219000261.png"\; state="\{\{state\}\}">RS</figure-callout>}}^2$ It is average SNR (its depend on the power of average path loss from transmitter to relay station, transmitter and at the noise-plus-interference level of relay station) in repeater v place experience.If for repeater v has distributed whole relaying power, ${\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{MS},v}={\stackrel{\&OverBar;}{G}}_{2,v}{P}_{\mathrm{RS}}/{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="MS"\; filenames="A20058005219000251.png,A20058005219000261.png"\; state="\{\{state\}\}">MS</figure-callout>}}^2$ Can be counted as mean virtual SNR in the cluster place of receiver experience.This mean virtual SNR depends on the total power constraint of path loss from relay station to receiver, relay station and at the noise-plus-interference level of receiver.

For the relaying of decoding forwarding type, amplifying parameters b _vQuilt is as giving a definition:

${\stackrel{\&OverBar;}{b}}_v^{\left(\mathrm{DF}\right)}=\sqrt{{\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{MS},v}}---\left(2b\right)$

Distribute if wish limit interferences, can select to be contemplated to the subclass that whole average SNR strengthens the repeater that maximum contribution is provided.For example, can select two " good " repeaters.The choice mechanism and the standard that in [3-4], propose be can use, but average channel gain rather than instantaneous channel gain are based on.

For the application with a plurality of receivers (for example mobile radio station), reasonably power control realizes making power to control in the transmitter of determining to occur in such as the base station, as shown in Figure 4.Power control is the receiver group of the similar propagation conditions of " aiming " experience preferably.Certainly, can use any other node to carry out power control calculates.Distributed solution according to the implementation described in the list of references [6-7] also can be provided, but use average channel gain rather than instantaneous channel gain.

Although above-mentioned power control scheme is a target with the group that experiences similar average propagation conditions, can organize the delivering power of adjusting repeater (and transmitter) for user or the user who experiences different average propagation conditionss.

Below will use the power division and the constant power of being advised to distribute to come assessed for performance.

Example performance

In following example, suppose with hexagon and place V=6 repeater (RS around the transmitter that starts such as base station (BS) ₁-RS ₆), and supposition is such as mobile radio station (MS ₁-MS ₆) and so on U receiver be placed on a segment distance that leaves transmitter, the twice of this distance the chances are transmitter-repeater distance.Basic configuration as shown in Figure 5.

At first, situation about transmitting is amplified in supposition.As providing in [6], the signal to noise ratio from receiver begins, by be each relay station (RS) v and each receiver (MS) μ introduce random phase factor exp ( ) revise this relation of opportunistic cooperation relaying.So the effective SNR about receiver (mobile radio station) μ is represented as:

Notice that the independent variable in the square root (3a) is an instantaneous value, and be used for b _vMean value compare, it reflects current and instantaneous channel conditions.

Under the situation that decoding is transmitted, effectively SNR can be written as:

For example, greedy chance algorithm can select to have the maximum effectively mobile radio station μ of SNR, promptly

${\mathrm{\&Gamma;}}_{\mathrm{Eff}}^{\left(\max \right)}=\max \{{\mathrm{\&Gamma;}}_{\mathrm{Eff},1},{\mathrm{\&Gamma;}}_{\mathrm{Eff},2},....{\mathrm{\&Gamma;}}_{\mathrm{Eff},U}\}---\left(4a\right)$

If perhaps average channel quality is slightly different

$\frac{{\mathrm{\&Gamma;}}_{\mathrm{Eff}}^{\left(\max \right)}}{{\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{Eff}}^{\left(\max \right)}}=\max \{\frac{{\mathrm{\&Gamma;}}_{\mathrm{Eff},1}}{{\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{Eff},1}},\frac{{\mathrm{\&Gamma;}}_{\mathrm{Eff},2}}{{\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{Eff},2}},....,\frac{{\mathrm{\&Gamma;}}_{\mathrm{Eff},U}}{{\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{Eff},U}}\}---\left(4b\right)$

So can determine Mean Speed performance R according to Shannon capacity.Herein, supposing needs two time slots (slot), and repeater reception and repeater after this transmit.Although can be genuine for transmitter-receiver to this, can per two time slots from the base station replace and be sent on the meaning of other repeater group and receiver cluster, this is disadvantageous.Therefore, also can remove 1/2 factor potentially.

$\stackrel{\&OverBar;}{R}=\frac{1}{2}E\left\{{\log }_2(1+{\mathrm{\&Gamma;}}_{\mathrm{Eff}}^{\left(\max \right)})\right\}---\left(5\right)$

The main assessment to the Rayleigh fading on the receiver link according to inverse probability (inverse power) the loss channeling and trunking device with α=3.5 amplified the performance of transmitting.Power is split by impartial between transmitter (base station) and repeater, i.e. P _BS=P _RS, and be provided with arbitrarily so that the magnitude of speed is 1b/s/Hz (being useful speed).For the configuration shown in Fig. 5, in Fig. 6, be illustrated as power control curve based on the result of equation (2a), (3a), (4) based on " on average ", this power control curve illustrates the relation of Mean Speed and mobile subscriber's number U.Also show constant power distribution curve, wherein b among Fig. 6 _v=constant.Also show the 3rd curve among Fig. 6, suppose that repeater best on average meaning is always selected and be assigned with whole power P _RSNotice that the scheme of being advised provides the performance of enhancing, especially when from the number of the moving body wherein selected greater than 2 the time.When comparing with the constant power allocation strategy or comparing, improved user data rate based on the power division of average link quality with the situation that is assigned to a via node when whole power.Fig. 7 has presented the curve about the same type of decoding forward relay.Wherein can see similar type and gain trend.

The constructive interference of the direct and repeating signal of parallel receive

In certain exemplary embodiments of the present invention, in based on the junction network of OFDM or OFDMA (OFDM access), multi-user diversity scheduling and following mechanism are used together, described mechanism be implemented in the receiving node parallel receive from the direct signal of origination node and repeating signal to provide directly and the constructive interference of repeating signal.In these two, data are modulated onto on a plurality of quadrature subcarriers that are transmitted in parallel at OFDM and OFDMA.In OFDM, data are sent to a user usually, and a plurality of user can receive data during the OFDM symbol of OFDMA.

Basically, consider the OFDM symbol, this symbol is formed and is sent at least one via node, and directly be sent to receiving node, so so that repeating signal and direct signal can be simultaneously or at least the time go up the cluster that enough closely arrives receiving node or selected node, to realize the constructive interference of OFDM symbol.Advantageously, the OFDM symbol that is extracted is not subjected to the influence of intersymbol interference basically.

With reference to the schematic example figure of figure 8, preferably, start transmission node 10 and via node 20 realize this point by suitably being disposed.For example, via node 20 can be a repeater of transmitting (on-frequency repeating) about frequency, each in the described repeater all received signal and under basically less than the situation of stand-by period of OFDM (OFDM) symbol duration with the same frequency band forward signal.Can use and Cyclic Prefix duration of adapting of the power delay profile (power delay profile) of the equivalent channel of repeating signal and direct signal dispose the transmission node 10 that starts, to guarantee parallel receive and constructive interference.Can be in the cyclic prefix module 18 of origination node 10 the configuration cycles prefix.

The formation of OFDM symbol is usually directed to IFFT (inverse fast fourier transform) and handles, inserts the protection interval of Cyclic Prefix and before sending it formed OFDM sign reversing is become radiofrequency signal at last.Correspondingly, receive the signal that is transmitted, and radio signal is converted into the OFDM symbol, Cyclic Prefix is removed and signal is carried out the FFT processing to obtain actual information at receiving terminal.

Comprising so-called frequency reradiating repeater (i.e. the repeater that can receive simultaneously and transmit), is known for the WCDMA system, but is not like this for the OFDMA system.Yet, need sizable relaying to gain and make that this thought is useful.Modern on-frequency repeater (for example those of Andrews Corp) can have the gain up to 95dB, interferes by the transmission of using signal processing technology (away from the antenna that separates) to eliminate himself again.Signal processing causes delay, and since symbol time to be far smaller than the delay that relaying introduces poor, current on-frequency repeater system does not consider directly and the constructive interference of repeating signal (one or more).Can solve this point by comprising, wherein the Cyclic Prefix path delay and the multipath transmisstion that are allocated such that the stand-by period at its absorption frequency forward relay station, cause owing to signal route via repeater based on Cyclic Prefix in OFDM System.

In this particular example, suppose that in V the repeater 20 at least one is on-frequency repeater, this transponder received signal and with same frequency it being transmitted immediately when receiving has also been forced delay T _RSThis delay can be owing to filter, amplify and because self-interference cancellation, promptly from himself amplifying signal of its interested signal cancellation that receives.Cyclic Prefix (CP) duration probably is arranged to T _CP＞T _RS+ T _DS+ T _P, T wherein _DSBe the maximum delay spread of every paths, T _PIt is poor to be that maximum path between relay route (one or more) and the directapath postpones.This set of CP duration has guaranteed can (for all practical purposes) to be extracted by the OFDM symbol that receives at any receiver of expectation in the overlay area expression of the no intersymbol interference (ISI) of ofdm signal in conjunction with the use of OFDM.Notice, through the OFDM symbol of different paths (promptly direct and relay route), with corresponding to (enough big) lap of identical OFDM symbol together by parallel receive.

Consider that not only transmitter arrives repeatered line (1) and repeater to receiver link (2), but also the consideration direct signal-in following formula, represent by (0), amplifying under the hypothesis of forward relay, the signal of the subcarrier k that is received by each u of receiving station can be written as:

$R_u\left(k\right)=H^{\left(0\right)}\left(k\right)\&CenterDot;S\left(k\right)+\underset{v=1}{\overset{V}{\mathrm{\&Sigma;}}}{H}_{u,v}^{\left(2\right)}\left(k\right)\&CenterDot;a_v\left(k\right)\&CenterDot;(H_v^{\left(1\right)}\left(k\right)\&CenterDot;S\left(k\right)+W_v\left(k\right))+W_u\left(k\right)---\left(6\right)$

Perhaps of equal valuely:

$R_u\left(k\right)=S\left(k\right)\&CenterDot;H_u^{\left(\mathrm{eff}\right)}\left(k\right)+W_u^{\left(\mathrm{eff}\right)}\left(k\right)---\left(6a\right)$

Wherein:

$H_u^{\left(\mathrm{eff}\right)}\left(k\right)=H^{\left(0\right)}\left(k\right)+\underset{v=1}{\overset{V}{\mathrm{\&Sigma;}}}{H}_{u,v}^{\left(2\right)}\left(k\right)\&CenterDot;a_v\left(k\right)\&CenterDot;H_v^{\left(1\right)}\left(k\right)---\left(6b\right)$

$W_u^{\left(\mathrm{eff}\right)}\left(k\right)=\underset{v=1}{\overset{V}{\mathrm{\&Sigma;}}}{H}_{u,v}^{\left(2\right)}\left(k\right)\&CenterDot;a_v\left(k\right)\&CenterDot;W_v\left(k\right)+W_u\left(k\right)---\left(6c\right)$

Can notice that wherein the ISI adjacent OFDM symbol is not related to and not necessarily must be included in the above-mentioned model.Interference (ISI) refers to the interference between the adjacent OFDM symbol between nomenclature.

Also should be noted that if two signal homophases, then have only parallel receive to the constructive interference of signal be possible.If two signal inversion, then parallel receive will cause the counteracting of OFDM symbol.Therefore, the present invention mainly is provided for realizing but not necessarily guarantees the necessary instrument of constructive interference.Yet additional optional feature of the present invention can be (if necessary), relatively the phase place of repeating signal and direct signal and to them one of them carries out phase shift, guarantee constructive interference thus.

Operate based on the MIMO/MISO in the wireless relay network of multi-user diversity

Fig. 9 is the schematic diagram based on the wireless cooperation junction network of the multi-user diversity of MIMO/MISO operation according to exemplary preferred embodiment of the present invention.

For such situation-when at least some start transmission node and receiving nodes are equipped with a plurality of antennas and are used based on the opportunistic communication scheme of MIMO-MISO, at least a portion via node can be equipped with one or more antennas, and one of them receiving node can be selected for the communication based on MIMO/MISO, richer to set up (rich) channel will soon further increase the channel of whole ETE channel capacity.

Especially, can be used to the spectrum efficiency that provides high based on the MIMO of spatial reuse.The feedback of this scheme is preferably described the channel quality vector of the quality of each MIMO subchannel.

Multiuser MIMO/MISO operation

For another kind of situation-when the transmission node that starts is equipped with a plurality of antennas and receiving node to be equipped with at least one antenna, the information of the spatial reuse that a plurality of receiving nodes can be selected and different can be guided and received by selected receiver.With all MIMO/MISO streams (sub-stream) of previous situation-wherein by spatial reuse and sent to a receiving node concurrently and compare, herein, MIMO and/or MISO flows by spatial reuse and is sent to different selected receiving nodes concurrently.The benefit of a kind of scheme in back is the performance that further strengthens, and this is because by selectional restriction not being allowed the bigger degree of freedom to receiving node only.The feedback of this scheme is preferably described the vector of the channel quality of each MIMO/MISO subchannel.

Use the wireless network of the grand diversity operation of multi-user diversity scheduling

In another aspect of the present invention, multi-user diversity is introduced into to be used for improving in distinctive mode the grand diversity of cordless communication network.

Figure 10 is the schematic diagram according to the wireless relay network of the grand diversity operation of the employing multi-user diversity scheduling of exemplary preferred embodiment of the present invention.At least two base stations 120 and two or more portable terminals 130 that wireless network mainly comprises controller 110, is connected with controller.Base station 120 is transmitted the same pilot signal concurrently, and each portable terminal 130 that receives pilot signal measure channel quality in dedicated channel mass measurement (CQM) module all.Each portable terminal 130 is given controller 110 feedback information about the measured channel quality of (all the way) on the way then, this controller 110 comprises multi-user diversity scheduler 116, and described multi-user diversity scheduler 116 is configured to dispatch according to the channel quality information (CQI) that receives the data of (or a plurality of) the selected terminal (one or more) that is used to be sent to portable terminal 130.At last, by base station 120 data are sent to selected portable terminal.Above-mentioned power control thought also is useful in the grand diversity of Figure 10 is used, for example by using control unit 118, described control unit 118 to small part is carried out power control calculating and is distributed delivering power to consider the base station to each according to the average link quality between base station and the portable terminal.Controller 110 can be radio network controller (RNC) or base station controller (BSC), and controller 110 for example can realize in the individual networks node, perhaps replacedly is integrated in the base-station node.

Below only described embodiment, should be appreciated that to the invention is not restricted to this with exemplary forms.The other modification, variation and the improvement that remain on the disclosure and claimed cardinal principle are all within the scope of the invention.

List of references

[1] Cooperative Diversity in Wireless Networks:Algorithms andArchitectures, the thesis for the doctorate of MA, Cambridge, the J.N.Laneman of the Massachusetts Institute of Technology, in August, 2002.

[2] with Dohler Mischa, Aghvami Abdol Hamid, Said Fatin, the publication No. of GhorashiSeyed AIi name is the international patent application of WO 03/003672A2, on January 9th, 2003.

[3] " Large-Scale Cooperative Relay Network with Optimal CoherentCombining under Aggregate Relay Power Constraints ", Peter Larsson, the procceedings of following teleconference (FTC2003), Beijing, China, 9-10 day in December, 2003.

[4] " Large-Scale Cooperative Relay Network with Optimal CoherentCombining under Aggregate Relay Power Constraints ", Peter Larsson and Hu Rong, the research WWRF8 of forum meeting that the world is wireless, the procceedings of working group 4, Beijing, 26-27 day in February, 2004.

[5] " Joint Cooperative Diversity and Scheduling in Low MobilityWireless Networks ", A.Wittneben, I.Hammerstr δ m and M.Kuhn, IEEE global telecommunication conference, Global Communications System in November, 2004,2004.

[6] U.S. Patent Application Publication No. 2004/0266339A1, Peter Larsson, on December 30th, 2004.

[7] U.S. Patent Application Publication No. 2005/0014464A1, Peter Larsson, on January 20th, 2005.

Claims (36)

1. the method for a trunk information in having the wireless relay network of a plurality of network nodes, described network comprise specifies origination node, at least one via node and at least two receiving nodes, and wherein said method may further comprise the steps:

-described appointment origination node transmits pilot signal;

-described at least one via node receives and transmits described pilot signal;

In-described the receiving node each receives described pilot signal and according to the pilot signal measurement channel quality that is received;

The described receiving node of-at least a portion will be given described appointment origination node about the feedback information of measured channel quality on the way;

The data dispatch that-described appointment origination node will be used for transmitting according to the channel quality information that is received is at least one selected node of described receiving node;

-described appointment origination node is sent to selected one or more receiving node via at least one identical via node of transmitting pilot signal with described data.

2. the method for claim 1, wherein said wireless relay network is the cooperating relay network.

3. method as claimed in claim 2, wherein said cooperating relay network are the auxiliary double bounce networks of relaying.

4. the method for claim 1, wherein said at least one via node comprises at least two via nodes, for pilot transmission, transmits described pilot signal concurrently and on same frequency, and for transfer of data, concurrently and on same frequency, transmit data.

5. method as claimed in claim 4 further comprises step: come in a plurality of selected via nodes each to distribute delivering power according to the average link quality of the link between described via node and described receiving node selected group to small part.

6. method as claimed in claim 5, the step of wherein said distribution delivering power are also based on the average link quality of the link between described origination node and selected via node described group.

7. the method for claim 1, wherein said scheduling step comprises:

-have peak based on those nodes of the tolerance of channel quality among select one or more receiving nodes and

The data that-selection is associated with selected one or more nodes are to be used for transmission.

8. the method for claim 1, wherein said network is based on OFDM (OFDM) or OFDMA (OFDM access), and described start transmission node and described at least one via node are suitable for implementation in described receiving node parallel receive from the direct signal of described origination node with from the repeating signal of described at least one via node, with provide described directly and the constructive interference of repeating signal.

9. method as claimed in claim 8, wherein said at least one via node can be operated the signal that receives from described origination node, and is transmitting signal with same frequency band under the situation less than stand-by period of OFDM symbol duration basically.

10. method as claimed in claim 8 or 9, wherein said OFDM (A) network is based on Cyclic Prefix in OFDM System (A) network, and use Cyclic Prefix to dispose described appointment transmission node, described Cyclic Prefix is suitable for the power delay profile of the equivalent channel of repeating signal and direct signal.

11. the method for claim 1, at least some in wherein said origination node, described at least one via node and the described receiving node have a plurality of antennas that are used for improved traffic operation.

12. method as claimed in claim 11, in the wherein said receiving node at least one and described origination node have a plurality of antennas that are used for the MIMO/MISO operation, and described at least one via node all has at least one antenna, and selects a receiving node to be used for the communication based on MIMO/MISO.

13. method as claimed in claim 12, wherein said MIMO operation is based on the MIMO operation of spatial reuse.

14. method as claimed in claim 11, wherein said origination node has a plurality of antennas, and described receiving node and described at least one via node all have at least one antenna, and select at least two receiving nodes to be used for based on parallel spatial multiplexing MISO or MIMO communication.

15. the system of a trunk information in having the wireless relay network of a plurality of network nodes, described network comprises specifies origination node, at least one via node and at least two receiving nodes, and wherein said system comprises:

-be used for transmitting the device of pilot signal in described appointment origination node;

-be used for receiving and transmitting the device of described pilot signal at described at least one via node;

-be used in each of described receiving node, receiving described pilot signal and according to the device of the pilot signal measurement channel quality that is received;

-be used for will giving the device of described appointment origination node about the feedback information of measured channel quality on the way at the described receiving node of at least a portion;

-be used for the data dispatch that will be used for transmitting according to the channel quality information that is received device at least one selected node of described receiving node in described appointment origination node;

-be used for via at least one identical via node of transmitting pilot signal described data being sent to the device of selected one or more receiving nodes in described appointment origination node.

16. system as claimed in claim 15, wherein said wireless relay network is the cooperating relay network.

17. system as claimed in claim 16, wherein said cooperating relay network is the auxiliary double bounce network of relaying.

18. system as claimed in claim 15, wherein said at least one via node comprises at least two via nodes, for pilot transmission, transmits described pilot signal concurrently and on same frequency, and for transfer of data, concurrently and on same frequency, transmit data.

19. system as claimed in claim 18 also comprises being used for to distribute the device of delivering power to a plurality of selected via nodes each according to the average link quality of the link between described via node and described receiving node selected group to small part.

20. system as claimed in claim 19, the wherein said device that is used to distribute delivering power is also based on the average link quality of the link between described origination node and selected via node described group.

21. system as claimed in claim 15, the wherein said device that is used to dispatch comprises:

-be used among those nodes of the channel quality with peak selecting the device of one or more receiving nodes; With

-be used to select the device of data that be associated with selected one or more nodes to be used to transmit.

22. system as claimed in claim 15, wherein said at least one via node is to amplify forward node.

23. system as claimed in claim 15, wherein said at least one via node is the decoding forward node.

24. system as claimed in claim 15, wherein said origination node are base stations and described receiving node is a portable terminal.

25. system as claimed in claim 15, wherein said network is based on OFDM (OFDM) or OFDMA (OFDM access), and described start transmission node and described at least one via node are suitable for implementation in described receiving node parallel receive from the direct signal of described origination node with from the repeating signal of described at least one via node, with provide described directly and the constructive interference of repeating signal.

26. system as claimed in claim 25, wherein said at least one via node can be operated the signal that receives from described origination node, and transmits signal with same frequency band under basically less than the situation of stand-by period of OFDM symbol duration.

27. as claim 25 or 26 described systems, wherein said OFDM (A) network is based on Cyclic Prefix in OFDM System (A) network, and described appointment origination node disposes by using Cyclic Prefix, and described Cyclic Prefix is suitable for the power delay profile of the equivalent channel of repeating signal and direct signal.

28. system as claimed in claim 15, at least some in wherein said origination node, described at least one via node and the described receiving node have a plurality of antennas that are used for improved traffic operation.

29. one kind for the equipment that uses in junction network, described equipment comprises:

-delivery module is used for transmitting pilot signal for channel quality measurement at least two receiving nodes, is received described pilot signal and it is forwarded to described receiving node by at least one via node;

-receiver module is used to receive the channel quality information from described receiving node;

-multi-user diversity scheduler is used for the data dispatch that will be used to transmit according to the described channel quality information that obtains from described receiving node at least one selected node to described receiving node;

-delivery module is used for via described at least one via node described data being sent to selected one or more receiving node.

30. equipment as claimed in claim 29, wherein said equipment is realized in network node.

31. a method that is used for the improved grand diversity operation of cordless communication network, described network comprise controller and at least two base stations, are used from and at least two communications of Mobile Terminals with described controller one, wherein said method comprises step:

Pilot signal is transmitted in-described base station;

In-described the portable terminal each receives described pilot signal and according to the pilot signal measurement channel quality that is received;

In-described the portable terminal each will be given described controller about the feedback information of measured channel quality on the way;

The data dispatch that-described controller will be used for transmitting according to the channel quality information that is received is at least one selected terminal of described portable terminal;

-via described base station described data are sent to selected one or more portable terminal.

32. method as claimed in claim 31 further comprises step: come in described at least two base stations each to distribute delivering power according to the average link quality of the link between described base-station node and described portable terminal selected group to small part.

33. a system that is used for the improved grand diversity operation of cordless communication network, described network comprises controller and at least two base stations, is used from and at least two communications of Mobile Terminals with described controller one, and wherein said system comprises:

-be used for transmitting the device of pilot signal in described base station;

-be used in each of described portable terminal, receiving described pilot signal and according to the device of the pilot signal measurement channel quality that is received;

-be used in each of described portable terminal, will giving the device of described controller about the feedback information of measured channel quality on the way;

-be used for the data dispatch that will be used for transmitting according to the channel quality information that is received device at least one selected terminal of described portable terminal at described controller;

-be used for described data being sent to the device of selected one or more portable terminals via described base station.

34. system as claimed in claim 33 further comprises being used for to distribute the device of delivering power to described at least two base stations each according to the average link quality of the link between described base-station node and described portable terminal selected group to small part.

35. one kind is used for the controller equiment that is connected with at least two base stations at cordless communication network, described base station is sent at least two portable terminals to be used for channel quality measurement with pilot signal, and wherein said controller equiment comprises:

-receiver module is used to receive the channel quality information based on pilot tone from described portable terminal;

-multi-user diversity scheduler is used for according to the described channel quality information based on pilot tone from described portable terminal acquisition, and the data dispatch that will be used for transmitting is at least one selected terminal of described portable terminal.

36. controller equiment as claimed in claim 35, wherein said controller equiment comprise radio network controller (RNC).

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